(n+2) x 4 = 20 /:4 n+2=5 n=3 (n - 10) x 3 = 9 /:3 n-10=3 n=13 (n+3) x 9 = 54 /:9 n+3=6 n= 3 3n + 7 = 16 3n =9 n=3 4n - 14 = 18 4n=32 n=8 9n- 20 = 70 9n=90 n= 10
(n+2) x 4 = 20 4n+8=20 n=3 (n - 10) x 3 = 9 3n-30=9 n=13 (n+3) x 9 = 54 9n+27=54 n=3 3n + 7 = 16 n=3 4n - 14 = 18 n=8 9n- 20 = 70 n= 10
(n+2) x 4 = 20 n= ? (n - 10) x 3 = 9 n=? 3n-30=9 3n=9-30 3n=-21 /3 n=-7 (n+3) x 9 = 54 n= ? 9n+27=54 9n=54-27 9n=27 /9 n=3 3n + 7 = 16 n=? 3n=16-7 3n=9 /3 n=3 4n - 14 = 18 n=? 4n=18+14 4n=32 /4 n=8 9n- 20 = 70 n= ? 9n=70+20 9n=90 /9 n=10
